| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2020 | 19.62 | 22.37 | 16.92 |
| 2019 | 18.27 | 23.68 | 14.58 |
| 2018 | 17.36 | 21.85 | 12.42 |
| 2017 | 23.12 | 30.24 | 16.13 |
| 2016 | 21.12 | 33.81 | 15.25 |
| 2015 | 22.73 | 44.31 | 13.45 |
| 2014 | 11.21 | 17.93 | 8.4 |
| 2013 | 13.84 | 19.57 | 10.88 |
| 2012 | 16.3 | 30.44 | 10.46 |
| 2011 | 22.2 | 36.76 | 11.87 |
| 2010 | 47.85 | 76.42 | 33.13 |
| 2009 | 39.1 | 64.65 | 13.08 |
| 2008 | 28.8 | 64.41 | 10.1 |
| 2007 | 46.09 | 79.2 | 17.26 |
| 2006 | 14.7 | 18.17 | 10.47 |
| 2005 | 16.56 | 29.63 | 10.73 |
| 2004 | 28.58 | 36.19 | 19.03 |
| 2003 | 40.97 | 51.41 | 19.66 |
| 2002 | 52.06 | 63.94 | 41.08 |
| 2001 | 53.37 | 65.95 | 41.53 |
| 2000 | 61.7 | 76.83 | 46.78 |
| 1999 | 41.69 | 66.79 | 27.53 |
| 1998 | 30.49 | 35.46 | 23.72 |